The primary structural component of a bicycle is the frame. Typically the bicycle frame comprises multiple tubes (a top tube and a down tube) that are rigidly secured to and extend between a head tube and a seat tube of a bicycle. The head tube provides a structural base to which the front wheel fork and handlebars are attached. The seat tube typically provides a base for a seat post which is normally telescopically received into the seat tube at a first end of the seat tube, and a saddle of the bicycle is secured to the seat post. A second end of the seat tube is rigidly attached to a bottom bracket, and the down tube is also rigidly attached to the bottom bracket. The top tube extends frontwardly from an upper end of the seat tube to the front tube.
Additionally, first ends of first and second chain stay members are rigidly attached to the bottom bracket and extend from the bottom bracket rearwardly. Additionally, first ends of first and second seat stay members are rigidly attached to the upper end of the seat tube. The first and second seat stay members and extend rearwardly and downwardly from the upper end of the seat tube, and second ends of the first and second seat stay members are rigidly attached to the second ends of the first and second chain stay members.
Typically the frame components discussed above are welded, brazed or bonded into a single rigid structure.
When a rider is on a bicycle having a rigid frame as discussed above, shocks due to surface irregularities are communicated through the frame to the seat and handle bars, causing discomfort and making it harder for the rider to pedal effectively. There have been many attempts to design bicycle frames that reduce shocks. For example, some bicycle frames incorporate suspension systems designed to absorb road shocks.